Attachment 18 Revised March 2022 Chesapeake Bay Program Office Most Effective Basins Funding Allocation In the U.S. Environmental Protection Agency's (EPA) Fiscal Year (FY) 2022 Appropriations Conference Report, $7.25 million was targeted to the Chesapeake Bay Program (CBP) Budget for "state-based implementation in the most effective basins." This document describes the methodology EPA followed to establish the most effective use of these funds and the best locations for these practices to be implemented to make the greatest progress toward achieving water quality standards in the Chesapeake Bay. EPA will use the same methodology and funding allocation that was used in FY 2021 for the $6 million allocation targeting agriculture and for the remaining $1.25 million supporting projects in underrepresented communities. Funding Priority 1: Agriculture The most effective basins to reduce the effects of excess nutrient loading to the Bay were determined considering two factors: cost effectiveness and load effectiveness. Cost effectiveness was considered as a factor to assure these additional funds result in state-based implementation of practices that achieve the greatest benefit to water quality overall. It was evaluated by looking at what the jurisdictions have reported in their Phase III Watershed Implementation Plans (WIPs) as the focus of their upcoming efforts, and by looking at the average cost per pound of reduction for best management practice (BMP) implementation by sector. Past analyses of cost per pound of reduction have shown that reducing nitrogen is less costly by far than reducing phosphorus.1 Based on that fact, EPA determined that the focus of this evaluation would be to target nitrogen reductions in the watershed. Evaluating the load reduction targets in all the jurisdictions' Phase III WIPs shows that the agricultural sector is targeted for 86 percent of the overall reductions identified to meet the 2025 targets collectively set by the jurisdictions. This means that most of the BMPs to be implemented in the watershed in the coming years are focused on the agricultural sector. On average, BMPs placed in the agricultural sector have been identified as the most cost effective BMPs. Data collected on BMP cost efficiency show the average cost per pound of nitrogen reduction for agricultural BMPs is approximately $24. This is much more cost-effective than the practices of stream restoration, shoreline erosion and sedimentation control that have been shown to cost about $354 per pound. Comparatively, the average cost of urban BMPs is roughly $2,259 per pound of nitrogen reduction, nearly 100 times that for agriculture. Based on this information, agricultural BMPs for reduction of nitrogen are the most cost effective to implement. Load effectiveness is a measure of the ability of management practices implemented in a given 1 The information, largely collected over a 15-year period by the Chesapeake Bay Program Office for use in the Partnership's Watershed Models, includes 1) the cost per unit of Best Management Practices (BMP), for over 200 BMPs, from contracted economists, and 2) the effectiveness of each BMP (the pounds of nutrients and sediment reduced per unit of BMP), mostly from "Expert Panels" made up of academics, agronomists, and practitioners working in the source sectors, including agriculture. The estimates of nutrient loads reduced to the Chesapeake Bay are from the G'-generation Chesapeake Bay Program Watershed Model [Chesapeake Bay Program, 2017. Chesapeake Assessment and Scenario Tool (CAST) Version 2017d. Chesapeake Bay Program Office, last accessed April 2020], 1 ------- Attachment 18 Revised March 2022 area (basin) to have a positive effect on dissolved oxygen in the Bay.2 Load effectiveness is the combination of three factors: land to water, delivery, and dissolved oxygen response. Each of these factors is described below. The land to water factor represents how nitrogen applied to the land moves through the soil and is transported to the water. It is a measure of the natural propensity of the landscape to deliver nitrogen to waterways. In the phase 6 model, this factor considers groundwater recharge rates, average available water capacity, and the fraction of land in the piedmont carbonate hydrogeomorphological region by basin to determine the average nitrogen load expected to reach the local streams and rivers. An area with a land-to-water factor of 1 will deliver twice as much nitrogen as an area with a land-to-water factor of 0.5, all else being equal. The land to water factor does not consider land management, which is a separate analysis of available reductions. The delivery factor is an estimate of the fraction of load reaching a stream, in a given basin, that will eventually make it to tidal waters. In the phase 6 model, it is calculated as a combination of stream and river factors. Stream factors generally apply to streams and reservoirs included in the National Hydrography Dataset that have an average annual flow less than 100 cubic feet per second and are calculated empirically using the USGS's SPARROW (SPAtially Referenced Regression On Watershed attributes) model. River factors apply to rivers and reservoirs with an annual flow greater than 100 cubic feet per second and are simulated by the CBP's Phase 6 dynamic model using HSPF (Hydrologic Simulation Program - Fortran). The final factor is a measure of the Bay's dissolved oxygen response to nutrient loads from different areas of the watershed. It is based on estuarine circulation patterns and biogeochemical transformations. In the 2017 estuarine Water Quality and Sediment Transport Model (this is the official title of the model used to evaluate dissolved oxygen response to nutrient input throughout the Bay), the oxygen response factor is calculated as the impact of a unit nitrogen load reduction on the critical segments or segments of the Bay. The critical segments were defined in the 2010 Chesapeake Bay Total Maximum Daily Load (Bay TMDL) as the set of segments where, if dissolved oxygen criteria are met, the remaining segments of the Bay will all meet their dissolved oxygen goals. These critical segments are the estuarine monitoring segments CB3MH, CB4MH, CB5MH, and POTMH for deep water and CB3MH, CB4MH, and CB5MH for deep channel. Each area of the watershed (basins) has a different effect on these critical segments. As an example, the Susquehanna River, located at the northern end of the Bay, has a greater effect on the dissolved oxygen in the deep water/deep channel area of the Bay than the James River, which is in the lower portion of the Bay. Nitrogen from the Susquehanna has a relatively long residence time in the Bay and must pass through the critical monitoring segments, while much of the nitrogen from the James passes out to the ocean through the Bay mouth. In order to evaluate the load effectiveness for a given basin, the phase 6 modeling suite was used to simulate the effect of nitrogen loading from agricultural lands in each identified basin. This evaluation included both the watershed model and the estuarine model. Through this evaluation a value of load effectiveness was assigned to each basin. This information was then used to 2 Load effectiveness is the same measure known as relative effectiveness used to calculate allocations as described in Section 6.3 of the 2010 Bay TMDL. It was also used to calculate Phase WIP III nitrogen planning targets in 2017. 2 ------- Attachment 18 Revised March 2022 determine which basins are the most effective at reducing the impact of nitrogen to the critical Bay segments identified in the previous paragraph. Funding Allocation Methodology EPA will provide the most effective basins funding for nitrogen reduction from the most cost- effective BMPs in the agricultural sector to the Chesapeake Bay watershed jurisdictions that have committed to reducing the agricultural contribution of nitrogen in their Phase III WIPs, i.e. Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia. The District of Columbia does not have an agricultural commitment through 2025. Using the state Phase III WIPs, EPA identified each state's nitrogen reduction commitment between now and 2025. The total load of these obligations to reduce nitrogen from Agriculture was added and then a percentage for each of those jurisdictions was determined. The $6 million Most Effective Basins (MEB) money will be allocated using the individual percentages for those jurisdictions to complete implementation work in the most effective basins identified within their boundaries. Table 1 shows, by jurisdiction, the percentage of agricultural sector implementation proposed in each WIP and the resulting MEB funding allocation. Table 1: MEB Funding Allocation by Jurisdiction Jurisdiction Phase III WIP Ag Nitrogen Commitment (million pounds) Percent of Total Nitrogen Commitment Proposed MEB Funding Allocations ($) DC 0.0 0.00% - DE 2.2 6.08% $ 364,540 MD 4.2 11.60% $ 695,940 NY 0.5 1.33% $ 79,536 PA 22.3 61.59% $ 3,695,112 VA 6.7 18.50% $ 1,110,191 wv 0.3 0.91% $ 54,681 Totals 36.2 100.00% $ 6,000,000 Determining the best locations for use of the additional funding for MEB comes from the rigorous evaluation that has been explained above. The charge given by Congress was to spend this money in the most effective basins. The questions to be answered are, what size basins provide the best and most targeted use of these funds to get the maximum load reduction possible? Where are the most effective basins located? Basins can be delineated in many shapes and sizes. For this evaluation, three different shape/size combinations were evaluated: Minor Basins, Hydrologic Unit Code3 (HUC) size 8 (HUC8), and River Segments. Two additional hybrid options, one from the Minor Basins, and one from the 3 Hydrologic Unit Code: The United States is divided and sub-divided into successively smaller hydrologic units. These hydrologic units are also known as watersheds. Each hydrologic unit is identified by a unique hydrologic unit code (HUC) consisting of two to twelve digits. The two-digit HUCs represent very large watersheds and each additional set of digits added decreases the size of the watershed. This division of watersheds is created using the National Hydrography Dataset (NHD). The NHD represents the nation's drainage networks and related features, including rivers, streams, canals, lakes, ponds, glaciers, coastlines, dams, and stream gages. 3 ------- Attachment 18 Revised March 2022 River Segments were created to place jurisdictional boundary lines over top of the Minor Basins and River Segments. There are 25 Minor Basins in the watershed, typically ranging in size from 680 square miles to 3,280 square miles. The basin sizes resulting from this method of segmentation vary greatly. An example of a Minor Basin is the Lower Potomac which covers approximately 2,580 square miles. These are very large tracts of land and may represent extremely varied land uses. At the HUC 8 scale, there are 53 basins that typically range in size from 810 square miles to 1,580 square miles. The basins are much more homogenous in size compared to the Minor Basin scale mentioned above. Although this segmentation is more homogenous, it still represents extremely varied land use within a basin. The third option is to divide the watershed by River Segments. The Phase 6 CBP Watershed Model divides the Chesapeake Bay watershed into 979 land-river segments, typically ranging from 10 to 100 square miles. These land-river segments were provided with attributes, including the name of the river. Segments with the same river name were combined to form 311 named rivers with a typical range of 70 to 250 square miles. Most named rivers are nested within river basins of different sizes. For example, Bobs Creek (170 square miles) is also part of the Juniata River (3,400 square miles) and Susquehanna River (27,500 square miles) but for this analysis carries the name attribute for Bobs Creek only. Segments designated as 'Juniata' are just the 770 square miles of river basin that are not part of any smaller system. This provides a much finer resolution scale and will have less varied land use in a basin. Finally, there are two different options to account for jurisdiction boundaries. These hybrid options were developed to overlay those boundaries over the Minor Basins and River Segments identified above. The 26 Minor Basins, divided further by jurisdictional boundaries, result in 43 State Minor Basin Segments, with a typical size of 270 square miles to 1600 square miles. Using the example of the Lower Potomac, there are now four divisions of this minor basin when segmenting by jurisdiction. These are the DC Lower Potomac - 60 square miles, MD Lower Potomac - 1040 square miles, and VA Lower Potomac - 1480 square miles. The 311 named River Segments, divided further by jurisdictional boundaries, result in 383 State-River Segments, with a typical size-range of 50 to 200 square miles. Each State-River Segment may be comprised of several land-river segments. This further division of the State River Basins is the same as described with the State Minor Basins. Based on our analysis, EPA has determined that the most appropriate scale or segmentation to be used in this allocation is the hybrid State-River segment scale. All the segmentation options were evaluated. The smaller scale provided much more focus than the larger scale segmentation which dampened the effectiveness of the smaller areas. This scale provides focus for the funds to be used in the most effective areas of the watershed. Each basin identified as being the most effective in each jurisdiction (except DC) has agricultural loading available to be reduced. This scale provides direction to the jurisdictions on where to target the funds they receive to reflect the intent of Congress most accurately in allocating this funding. The effect of nitrogen to the critical Bay segments as a ratio of pounds delivered to dissolved oxygen response for each of the 383 river segment basins identified can be found in the Most Effective Basins Funding Allocations Rationale (updated May 2021). The basins are shown in 4 ------- Attachment 18 Revised March 2022 order of load effectiveness. The table also shows the amount of nitrogen reduced in that basin to date based on reporting by jurisdictions, remaining nitrogen load to be reduced in those basins (from modeling runs), and the size of the basin. At an average cost of $24 per pound of reduction of nitrogen, $6 million for implementation of BMPs in the MEBs should result in approximately 250,000 pounds of nitrogen reduction overall. Table 2 below shows the most effective basins in which implementation using these funds is to occur. Table 2: Most Effective Basins Ranked by Total Nitrogen (TN) Reduction Effectiveness Rank Jurisdiction State Rivers TN Effectiveness 1 PA York Indian Rock Dam 23.68 2 PA Black Creek 18.97 3 PA Safe Harbor Dam 18.83 4 PA Codorus Creek 18.27 5 PA Little Swatara Creek 17.67 6 PA Chiques Creek 17.08 7 PA Conestoga Creek 16.74 8 PA Pequea Creek 16.09 9 PA Deer Creek 15.55 10 PA Catawissa Creek 15.42 11 PA Mill Creek 15.30 12 PA Shamokin Creek 15.26 13 PA Codorus Creek West Branch 15.16 14 PA Mahanoy Creek 15.12 15 PA Nescopeck Creek 15.04 16 MD Jones Falls 14.95 17 PA Swatara Creek 14.89 18 PA Roaring Creek 14.88 19 PA Mahantango Creek 14.74 20 MD Little Pipe Creek 14.74 21 PA Octoraro Creek 14.72 22 WV Stony River 14.51 23 MD Deer Creek 14.46 24 PA Alvin R. Bush Dam 14.28 25 PA Sinnemahoning Creek 14.18 26 PA Middle Creek 14.12 27 PA Cocalico Creek 14.04 28 PA East Licking Creek 13.96 29 PA Buffalo Creek 13.95 30 PA Tuscarora Creek 13.93 31 WV Mt. Storm Power Station Dam/StoRiver Dam 13.92 5 ------- Attachment 18 Revised March 2022 32 PA Larrys Creek 13.91 33 PA Wiconisco Creek 13.87 34 MD Bloomington/Jennings Randolph 13.67 35 PA Codorus Creek South Branch 13.63 36 PA Wills Creek 13.31 37 PA Fishing Creek 13.31 38 PA Juniata River 13.28 39 MD Tonoloway Creek 13.17 42 VA Lower Eastern Shore Tidal Drainage 12.94 60 WV Potomac River North Branch 12.09 67 VA Pocomoke River 11.73 83 DE Lower Eastern Shore Tidal Drainage 10.90 86 NY Owego Creek 10.71 88 DE Nanticoke River 10.66 103 VA Great Wicomico River 10.11 118 DE Middle Eastern Shore Tidal Drainage 9.59 121 NY Tioughnioga Creek 9.44 125 NY Tioughnioga River West Branch 9.26 Funding Priority 2: Underrepresented Communities In FY 2021, an additional $1.25 million was appropriated for "state-based implementation in the most effective basins." EPA and the Chesapeake Bay Partnership have renewed their commitment and focus on inclusion and equity with regard to historically underrepresented communities, including communities of color and communities of lower socioeconomic status. EPA is focusing this additional funding allocation on those areas that have been identified as being most effective for improving water quality while targeting underrepresented communities. The allocation for this funding will follow the same funding allocation used for the Chesapeake Bay Implementation Grants (CBIG). The CBIG allocation formula awards funds to the seven jurisdictional partners in the following manner: a 20% share goes to MD, PA, and VA, a 10% share goes to DC, DE, NY, and WV. The following table shows the breakdown for this $1.25 million appropriation. Table 3: MEB Funding Allocation by Jurisdiction (Remaining $1.25 Million) Jurisdiction CBIG Percentage Split MEB Funding Allocation ($) DC 10% $ 125,000 DE 10% $ 125,000 MD 20% $ 250,000 NY 10% $ 125,000 PA 20% $ 250,000 VA 20% $ 250,000 6 ------- Attachment 18 Revised March 2022 Jurisdiction CBIG Percentage Split MEB Funding Allocation ($) WV 10% $ 125,000 Totals 100% $ 1,250,000 The selection of MEBs for this funding allocation of 1.25 million dollars will look at two factors: underrepresented communities and load effectiveness. Underrepresented communities will be identified based on demographic metrics from the American Community Survey which are available on the EPA Environmental Justice Screening and Mapping Tool. Low income is defined as ratio of income to cost of living that is less than two. Data is presented as a census block group with a percentage of population that is low income >=50%. Communities of color are defined as all other ethnicities other than Caucasian. Data is presented as a census block group with a percentage of people of color population >= 37%. 37% is chosen to mirror the national percentage of people of color. These definitions come from work completed by the CBP Diversity Workgroup where they provided "best professional judgement" in terms of interpreting two of the metrics (communities of color and low income) to help rank areas for composite conservation and restoration benefits. Load Effectiveness for this analysis was completed in the exact same manner as it was described on page 3 of this document with one exception. These MEBs are the result of evaluating the effect of all nonpoint source loads of nitrogen instead of just loads of nitrogen from agriculture. Additionally, the scale used to determine these MEBs is the State-River basin segmentation that was described in the earlier analysis. Table 4 shows the list of Most effective basins that overlay the areas that have been identified as underrepresented communities. The most effective basins for focusing this funding are shown in gray highlight. This list has been expanded compared to the FY 2021 list of eligible basins to allow jurisdictions more flexibility in reaching underrepresented communities in their respective jurisdictions. Table 4: Most Effective Basins that Overlay Areas Identified as Underrepresented Communities (As Represented by Gray Highlighted) Rank Jurisdiction State-Rivers TN Effectiveness TN Reductions Made to Date TN Load Remaining to Reduce Watershed Size (sq. mi.) 1 PA York Indian Rock Dam 22.87 14237 218825 21 1 PA Black Creek 19.39 27953 63440 62 3 PA Codorus Creek 19.11 9916 367864 66 4 PA Safe Harbor Dam 17.51 107726 799160 114 5 PA Chiques Creek 17.16 551740 1857828 126 6 PA Conestoga Creek 16.68 953008 3007086 278 7 PA Little Swatara Creek 16.34 0 1110781 99 8 PA Pequea Creek 16.12 403680 1865801 155 9 PA Shamokin Creek 16.08 12615 332191 137 10 PA Mahanoy Creek 15.96 17014 382719 157 11 PA Mill Creek 15.58 220956 668640 56 12 PA Octoraro Creek 15.11 259512 1974658 176 7 ------- Attachment 18 Revised March 2022 13 PA Deer Creek 15.06 25340 218681 25 14 PA Catawissa Creek 14.86 21243 301544 153 15 WV Stony River 14.59 2004 10285 10 16 PA Codorus Creek West Branch 14.58 31409 308201 50 17 MD Little Pipe Creek 14.42 304558 517846 83 18 PA Swatara Creek 14.32 219465 1600423 396 19 MD Deer Creek 14.11 201343 626682 146 20 PA Cocalico Creek 14.1 303655 1094543 140 21 PA Mahantango Creek 14.08 124321 793410 165 22 PA Roaring Creek 13.84 27979 330495 88 23 PA Nescopeck Creek 13.83 94098 167141 112 24 PA Wiconisco Creek 13.8 181818 368808 116 25 MD Bloomington/Jennings Randolph 13.64 10882 41235 63 26 PA Middle Creek 13.64 0 817242 177 27 WV Mt. Storm Power Station Dam/Stony River Dam 13.53 9634 58170 49 28 MD Susquehanna River 13.37 9581 65361 28 29 PA East Licking Creek 13.37 10549 76561 46 30 VA Lower Eastern Shore Tidal Drainage 13.26 145008 1224541 219 31 MD Savage River Dam 13.25 13567 30384 56 32 PA Tuscarora Creek 13.08 38911 590526 224 33 PA Sherman Creek 12.93 0 778438 276 34 MD Octoraro Creek 12.84 51357 123333 35 35 PA Codorus Creek South Branch 12.81 45232 703913 117 36 PA Buffalo Creek 12.79 28828 859729 207 37 PA Alvin R. Bush Dam 12.78 1196 18824 95 38 PA Juniata River 12.71 207199 1992742 767 39 PA Larrys Creek 12.69 32513 83963 89 40 PA Susquehanna River 12.62 1360081 4779581 2262 41 PA Penns Creek 12.59 107376 1115206 377 42 PA Fishing Creek 12.5 96073 653637 271 43 MD Potomac River North Branch 12.36 62959 136977 157 44 MD Conowingo Dam 12.24 13275 42727 23 45 WV Bloomington/Jennings Randolph 12.21 1663 70956 81 46 MD Muddy Creek 12.08 1003 4615 2 47 WV Potomac River North Branch 12.06 18036 160819 162 48 MD Monocacy River 11.99 1008035 1657042 448 49 PA Sinnemahoning Creek 11.99 5284 11534 72 8 ------- Attachment 18 Revised March 2022 50 MD Lingamore Creek 11.88 212204 380907 89 51 PA Chillisquaque Creek 11.87 77137 545406 112 52 PA Warrior Ridge Dam 11.87 15990 129815 78 53 PA Susquehanna River West Branch 11.78 348229 2137577 1745 54 PA Holtwood Dam 11.73 9014 242256 50 55 PA Bald Eagle Creek 11.71 151794 600282 383 56 PA Aughwick Creek 11.7 9009 94102 47 57 VA Pocomoke River 11.67 5584 108298 24 58 MD Jones Falls 11.66 5654 170604 58 59 PA Muddy Creek 11.66 50272 855327 137 60 MD Lower Western Shore Tidal Drainage 11.64 27704 714109 275 61 MD Savage River 11.64 17958 42274 60 62 PA White Deer Creek 11.52 0 20073 45 63 PA Broad Creek 11.51 99 2602 1 64 MD Big Pipe Creek 11.48 281098 507253 109 65 PA Cush Creek 11.46 94404 608556 191 66 MD Middle Western Shore Tidal Drainage 11.42 7177 332988 118 67 PA Foster Joseph Sayers Dam 11.42 26444 120565 73 68 MD Broad Creek 11.34 62779 140252 40 69 PA Beech Creek 11.32 6483 72132 171 70 PA George B. Stevenson Dam 11.25 1764 2925 27 71 PA Little Juniatta River 11.1 68670 728326 343 72 DE Nanticoke River 11 112513 1009792 91 73 PA Blacklog Creek 10.98 6420 77292 73 74 DE Lower Eastern Shore Tidal Drainage 10.96 100031 2012862 232 75 PA Conowingo Dam 10.9 109679 850259 102 76 MD Wills Creek 10.88 14380 44297 61 77 PA Conogoguinet Creek 10.84 0 2397677 458 78 PA Huntington Creek 10.82 72545 114179 114 79 PA Big Elk Creek 10.73 88005 349503 42 80 PA Wills Creek 10.73 39775 283946 193 81 PA Bennette Branch 10.54 24401 96810 377 82 PA Quittapahilla Creek 10.39 23640 643461 77 83 PA Conococheague Creek West Branch 10.37 0 1212735 198 84 PA Texas Creek 10.36 45659 117707 180 85 PA Muncy Creek 10.32 119615 318205 204 86 VA Great Wicomico River 10.26 59620 370341 128 87 PA Meshoppen Creek 10.15 126494 132856 115 88 PA Yellow Breeches Creek 10.05 0 744883 220 9 ------- Attachment 18 Revised March 2022 89 WV Back Creek 10 0 109425 106 90 MD Little Conococheague Creek 9.97 24013 57469 17 91 PA Kettle Creek 9.97 3104 56482 152 92 PA Moshannon Creek 9.95 16234 149836 274 93 PA Driftwood Branch 9.94 34099 14962 95 94 MD Tonoloway Creek 9.9 623 3070 2 95 MD Licking Creek 9.87 7539 29706 27 96 PA Conococheague Creek 9.84 891 1981838 304 97 PA Juniata River Frankstown Branch 9.81 1887 935455 396 98 NY Owego Creek 9.72 14266 21236 13 99 MD Nanticoke River 9.71 53543 120930 20 100 MD Winters Run 9.7 18598 186226 58 101 PA Bowman Creek 9.7 50820 60678 120 102 MD Conococheague Creek 9.63 102907 282130 66 103 WV Sleepy Creek 9.63 16944 86747 125 104 DE Middle Eastern Shore Tidal Drainage 9.61 15869 124020 19 105 PA Lycoming Creek 9.61 42472 199800 273 106 MD Potomac River 9.6 320501 799081 373 107 MD Big Elk Creek 9.56 4727 24146 11 108 PA Branch Creek 9.56 0 214490 46 109 PA Wallis Run 9.55 5586 19906 37 110 PA Cayuta Creek 9.53 2067 5048 2 111 MD Great Seneca Creek 9.35 122870 214447 102 112 PA Sinnemahoning Creek First Fork 9.33 7362 77126 240 113 MD Antietam Creek East Branch 9.32 9267 22410 8 114 PA Potomac River 9.3 1140 12444 3 115 PA Wyalusing Creek 9.3 222476 245752 220 116 MD Upper Western Shore Tidal Drainage 9.29 42521 264224 141 117 PA Pine Creek 9.24 57915 219806 599 118 PA Sideling Hill Creek 9.23 19918 384431 284 119 MD Middle Eastern Shore Tidal Drainage 9.2 638248 1771391 348 120 PA Licking Creek 9.19 27154 407836 186 121 PA Conewago Creek 9.11 282392 1775750 510 122 PA Lackawanna River 9.07 33808 206810 348 123 DC Bull Run 8.93 0 4086 20 124 MD Gunpowder Falls 8.92 84899 376374 175 125 PA Little Northeast Creek 8.9 2852 66473 8 126 PA Loyalsock Creek 8.9 43639 204007 377 10 ------- Attachment 18 Revised March 2022 127 MD Georges Creek 8.75 14601 37387 75 128 MD Choptank River 8.73 139913 551765 108 129 MD Lower Patuxent Tidal Drainage 8.65 75751 562738 300 130 WV Cacapon River 8.63 3814 22942 61 131 MD Antietam Creek 8.58 262951 641720 178 132 MD Marshyhope Creek 8.52 221074 589651 119 133 VA Sleepy Creek 8.52 0 15459 20 134 MD Loch Raven Dam 8.43 3790 45168 31 135 VA South Branch Potomac 8.39 0 69628 59 136 MD Seneca Creek 8.38 38860 75753 27 137 PA Mehoopany Creek 8.38 28506 41128 123 138 DE Deep Creek 8.37 3913 233516 30 139 WV Potomac River 8.37 53672 433956 320 140 MD Western Run 8.32 83020 295407 118 141 PA Little Conococheague Creek 8.32 0 517 1 142 PA Spring Creek 8.29 94318 363288 146 143 WV Potomac River South Branch 8.26 107838 573565 543 144 MD Evitts Creek 8.2 5098 20560 31 145 NY Nanticoke Creek 8.2 78095 106981 114 146 MD Little Northeast Creek 8.19 59312 161058 48 147 PA Curwensville Dam 8.18 11604 27207 53 148 MD Hunting Creek 8.16 203 44248 26 149 NY Tioughnioga River West Branch 8.15 192589 180026 104 150 WV Opequon Creek 8.13 31496 403725 192 151 VA Potomac River South Branch North Fork 8.11 577 7336 38 152 DC Potomac River 8.09 401 30511 14 153 MD Marsh Run 8.06 26001 78497 21 154 MD Lower Potomac Tidal Drainage 8.05 60460 716945 428 155 PA Antietam Creek East Branch 7.97 0 429574 86 156 NY Tioughnioga River 7.95 243695 220389 208 157 MD Middle Patuxent River 7.92 89327 148208 58 158 WV North River 7.89 13878 198766 206 159 NY Tioughnioga Creek 7.88 227968 239600 193 160 VA Lower Potomac Tidal Drainage 7.87 83589 563421 470 161 MD Marsh Creek 7.83 22088 40985 11 162 MD Nassawango Creek 7.82 129103 130002 68 163 WV Reeds Creek 7.73 1563 18853 65 11 ------- Attachment 18 Revised March 2022 164 NY Susquehanna River 7.72 682455 751626 890 165 DC Anacostia River 7.71 1380 37452 18 166 MD Lower Eastern Shore Tidal Drainage 7.67 805230 1713780 454 167 PA Tonoloway Creek 7.67 13483 261108 112 168 MD North East Branch Anacostia River 7.61 7435 103822 75 169 WV Potomac River South Branch North Fork 7.5 16538 113755 212 170 MD Chester River 7.49 70737 161788 35 171 PA Chest Creek 7.45 42823 152933 129 172 MD Patuxent River 7.43 70154 259029 176 173 PA Fifteen Mile Creek 7.43 788 8244 12 174 MD Tuckahoe River 7.42 222241 657718 150 175 NY Owego Creek East Branch 7.4 88049 97821 101 176 NY Chenango River 7.37 621464 577651 614 177 NY Catatonk Creek 7.36 105054 135579 151 178 MD Patapsco River 7.35 96286 355979 204 179 PA Antietam Creek 7.33 0 155266 20 180 PA Monocacy River 7.29 10592 116224 67 181 PA Little Tonoloway Creek 7.28 0 12888 10 182 MD Pocomoke River 7.19 817630 915510 301 183 MD Upper Eastern Shore Tidal Drainage 7.19 1181710 2867947 748 184 MD Catoctin Creek 7.16 178014 314785 120 185 VA Shenandoah River South Fork 7.14 38566 1299039 618 186 DC Rock Creek 7.1 134 15957 10 187 DE Upper Eastern Shore Tidal Drainage 7.09 51447 148987 36 188 PA Little Loyalsock Creek 7.08 25054 85224 82 189 WV Shenandoah River 7.08 12912 48460 103 190 MD Fifteen Mile Creek 7.07 1606 15025 50 191 PA Marsh Creek 7.06 86013 488599 161 192 WV South Branch Potomac 7.06 43742 188358 208 193 PA Sugar Creek 7.04 176783 262318 190 194 MD Conococheague Creek West Branch 7 0 98 0 195 VA Back Creek 6.98 751 155817 309 196 VA Shenandoah River 6.98 12912 48460 249 197 MD Little Tonoloway Creek 6.96 5857 18895 15 198 NY Owego Creek West Branch 6.95 49514 64209 77 12 ------- |